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/* Copyright (C) 2019 Jeremy Thien <jeremy.thien@gmail.com>
This file is part of the JWT C Library
This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <stdio.h>
#include <stdlib.h>
#include <jwt.h>
#include <getopt.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <libgen.h>
void usage(const char *name)
{
/* TODO Might want to support JWT input via stdin */
printf("%s --key some-pub.pem --alg RS256 some-file.jwt\n", name);
printf("Options:\n"
" -k --key KEY The key to use for verification\n"
" -a --alg ALG The algorithm to use for verification\n"
" -c --claim KEY=VALUE Verify JWT has claim KEY with VALUE\n");
exit(0);
}
int main(int argc, char *argv[])
{
int exit_status = 0;
char opt_key_name[200] = "test-rsa256-pub.pem";
jwt_alg_t opt_alg = JWT_ALG_RS256;
char opt_jwt_name[200] = "test-rsa256.jwt";
int claims_count = 0;
int i = 0;
unsigned char key[10240];
size_t key_len;
FILE *fp_pub_key;
char jwt_str[2048];
size_t jwt_len;
FILE *fp_jwt;
int ret = 0;
jwt_valid_t *jwt_valid;
jwt_t *jwt = NULL;
int oc = 0;
char *optstr = "hk:a:c:";
struct option opttbl[] = {
{ "help", no_argument, NULL, 'h' },
{ "key", required_argument, NULL, 'k' },
{ "alg", required_argument, NULL, 'a' },
{ "claim", required_argument, NULL, 'c' },
{ NULL, 0, 0, 0 },
};
char *k = NULL, *v = NULL;
struct kv {
char *key;
char *val;
} opt_claims[100];
memset(opt_claims, 0, sizeof(opt_claims));
while ((oc = getopt_long(argc, argv, optstr, opttbl, NULL)) != -1) {
switch (oc) {
case 'k':
strncpy(opt_key_name, optarg, sizeof(opt_key_name));
opt_key_name[sizeof(opt_key_name) - 1] = '\0';
break;
case 'a':
opt_alg = jwt_str_alg(optarg);
if (opt_alg == JWT_ALG_INVAL) {
fprintf(stderr, "%s is not supported algorithm, using RS256\n", optarg);
opt_alg = JWT_ALG_RS256;
}
break;
case 'c':
k = strtok(optarg, "=");
if (k) {
v = strtok(NULL, "=");
if (v) {
opt_claims[claims_count].key = strdup(k);
opt_claims[claims_count].val = strdup(v);
claims_count++;
}
}
break;
case 'h':
usage(basename(argv[0]));
return 0;
default: /* '?' */
usage(basename(argv[0]));
exit(EXIT_FAILURE);
}
}
if (optind == argc) {
fprintf(stderr, "Please provide name of jwt file\n");
exit(EXIT_FAILURE);
}
strncpy(opt_jwt_name, argv[optind], sizeof(opt_jwt_name) - 1);
opt_jwt_name[sizeof(opt_jwt_name) - 1] = '\0';
fprintf(stderr, "jwt verification: jwt %s pubkey %s algorithm %s\n",
opt_jwt_name, opt_key_name, jwt_alg_str(opt_alg));
/* Load pub key */
fp_pub_key = fopen(opt_key_name, "r");
key_len = fread(key, 1, sizeof(key), fp_pub_key);
fclose(fp_pub_key);
key[key_len] = '\0';
fprintf(stderr, "pub key loaded %s (%zu)!\n", opt_key_name, key_len);
/* Load jwt */
fp_jwt = fopen(opt_jwt_name, "r");
jwt_len = fread(jwt_str, 1, sizeof(jwt_str), fp_jwt);
fclose(fp_jwt);
jwt_str[jwt_len] = '\0';
fprintf(stderr, "jwt loaded %s (%zu)!\n", opt_jwt_name, jwt_len);
/* Setup validation */
ret = jwt_valid_new(&jwt_valid, opt_alg);
if (ret != 0 || jwt_valid == NULL) {
fprintf(stderr, "failed to allocate jwt_valid\n");
goto finish_valid;
}
jwt_valid_set_headers(jwt_valid, 1);
jwt_valid_set_now(jwt_valid, time(NULL));
for (i = 0; i < claims_count; i++) {
jwt_valid_add_grant(jwt_valid, opt_claims[i].key, opt_claims[i].val);
}
/* Decode jwt */
ret = jwt_decode(&jwt, jwt_str, key, key_len);
if (ret != 0 || jwt == NULL) {
fprintf(stderr, "invalid jwt\n");
exit_status = 1;
goto finish;
}
fprintf(stderr, "jwt decoded successfully!\n");
/* Validate jwt */
if (jwt_validate(jwt, jwt_valid) != 0) {
fprintf(stderr, "jwt failed to validate: %08x\n", jwt_valid_get_status(jwt_valid));
jwt_dump_fp(jwt, stderr, 1);
exit_status = 1;
goto finish;
}
fprintf(stderr, "JWT is authentic! sub: %s\n", jwt_get_grant(jwt, "sub"));
jwt_dump_fp(jwt, stdout, 1);
finish:
jwt_free(jwt);
finish_valid:
jwt_valid_free(jwt_valid);
return exit_status;
}
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